THE CBANBERBY SPAXWORM. 23 
opposite extremity. The color varies to a considerable extent from 
mottled pale yellowish to brown, often with an olivaceous or greenish 
tint. Those which have been recently captured in the District of 
Columbia are reddish brown, mottled, streaked, and lined with lighter 
yellowish, red. and black. The head is strongly marked with trans- 
verse irregular black bands. The thoracic segments are marked 
above by a pair of thin median longitudinal line-. The second 
abdominal segment bears on the dorsal surface a pair of prominent, 
widely separated, mostly black tubercles, but in some individuals 
these are wanting. The penultimate segment also bears above a 
smaller pair of black tubercles. The larva when full grown measures 
an inch to upward of an inch and a fourth in length (25-33 mm ) and 
the greatest diameter is about one-eighth of an inch (3 mm ) . The singu- 
lar construction of the legs, or rather the lack of the intermediate legs 
usually present in caterpillars of other families, is the cause of the 
peculiar motions of the spanworms in crawling about in search of 
food, which have given them their popular names. When in motion 
a larva extends its body to full length, then brings the posterior In- 
close to the anterior ones, causing the body to loop in the center. 
The body is then stretched out again, these actions being repeated 
alternately. 
When this spanworm is in repose it attaches itself to the foliage — 
for example, to the stem of asparagus — by means of its anal pair of 
legs and stretches out its body rigidly and at an angle so that its 
natural colors harmonize with the foliage or with the landscape. 
On this head Doctor Smith has remarked that on a section of cran- 
berry bog on which this species is feeding the observer may stand in 
the midst of thousands of them and see none until something start- 
them into motion. Then it appears almost as though the entire bog 
were alive. As the spawnworms hang somewhat tenaciously to their 
food plants, they are undoubtedly present frequently in numbers 
without anyone being the wiser. 
The half -grown larva is described by Doctor Forbes. 8 
The pupa, shown, ventral view, in figure 6 at <L is of robust form. 
light greenish brown in color, and a little less than half an inch in 
length (12 mm ) and about a third of that (4 mm ) in width. 
DISTRIBUTION. 
The wide distribution of this inseel is shown by the following li<t 
of localities, based upon Doctor Packard's list, where the authorities 
for each locality are given: Maine; Amherst, ('ape Cod. Cotuit, 
Nfatick, Mass.: West Farms, ('enter. Albany, and Brewster, X. Y. : 
Philadelphia. Pa.: Lansing, Mich.; Dayton. Ohio (Pilate); Glen- 
coe, Nebr.; Cadet, Mo.; Centralis and elsewhere in Illinois: Wash- 
ington and Brookland, D. C. : Georgia; Calhoun. Dawson, and De- 
